Lactoferrin and cyclic lactoferricin inhibit the entry of human cytomegalovirus into human fibroblasts.
Antiviral Res. 2001 Aug;51(2):141-9. PMID: 11431038
Lactoferrin is mainly produced by polymorphonuclear leukocytes and has been demonstrated in mammalian milk and external secretions. Lactoferrin is an iron-binding, multifunctional protein and may play an important role in immune regulation and in defense mechanisms against bacteria, fungi and viruses. Lactoferricin is a potent antimicrobial peptide generated from the N-terminal part of lactoferrin by pepsin cleavage. We demonstrate that lactoferrins from different species and its N-terminal peptide lactoferricin (particularly the cyclic form) inhibit expression of early and late antigens, as well as production of infectious viral progeny during human cytomegalovirus (HCMV) infection in vitro. Iron-saturated lactoferrin did not affect HCMV antigen expression. Heparin had the same effects as iron-depleted lactoferrin. Yet, mixtures of lactoferrin and heparin did not inhibit HCMV multiplication i.e. lactoferrin and heparin seemed to mutually block each other's antiviral activities. HCMV-infected cells exposed to lactoferrin and cyclic lactoferricin contained less intracellular virus than unexposed cells. The antiviral activity of cyclic lactoferricin was more than seven-fold weaker than that of the maternal molecule. Lactoferrin and cyclic lactoferricin prevented HCMV entrance into the host cell.